I've been meaning to do this for days
Coda to an Epilogue: Twenty Years Later, Or The Kids Are All Right by Maya
This is gen, Harry and Draco friendship specifically, and it's absolutely hilarious. Draco and Harry end up in the sewers beneath Durmstrang looking for their missing children, James and Albus, and Scorpius. All the characters are so well crafted and the children are a hoot, especially Scorpius who is just like his father but not. This is the same author who is writing the brilliant H/D
Drop Dead Gorgeous (WIP) and the side story The Way We Get By (Complete) which you should also catch if you can as it's one of the best H/D's out there.
This latest fic is in three parts, is complete and actually makes the official epilogue bearable. I can't recommend it enough.